1. Field of the Invention
The invention relates to a device for dosed proportioning and cutoff of air supply devices feeding primary combustion air into the primary heating space of a coke oven chamber, the device being configured as a cover that can be stage-wise moved away from the air supply device so as to be able to exactly regulate the quantity of air streaming in. The number of stages may range from two stages to an indefinite number of stages so as to be able to regulate the entering stream of air in an arbitrarily fine manner. At the same time, this device also serves to cover the air supply device against weather impacts. The device distinguishes itself from prior art in technology in that it is situated outside the coke oven chamber on the air supply device, thus being easily accessible. Owing to the arrangement of this device, the dosed proportioning can be easily controlled and even be automated. The present invention also relates to a method for dosed proportioning of primary combustion air in a primary heating space of a coke oven chamber with the inventive device.
2. Description of the Related Art
Coking gas evolving on coal carbonization possesses a remarkable calorific value. To achieve a uniform distribution of coking heat generated in non-conventional coke oven chambers by combustion of coking gas, the coking gas is burnt in two steps. The evolving coking gas is initially conducted into a gas space located above the coke cake within the coke oven chamber where it is burnt with a sub-stoichiometric quantity of air. This air is called primary air or primary combustion air. The gas space above the coke cake is frequently called the “primary heating space.” Partly burnt coking gas from the primary heating space is then passed via so-called “downcomer” channels into a “secondary heating space” where the coking gas is completely burnt. Thereby, the coke cake is also heated from below, thus achieving uniform heating of the coke cake from all sides. This leads to an improved and—above all—uniform quality of coke produced.
Carbonization of coal is often accomplished in coke ovens of the “Non-Recovery” or “Heat-Recovery” type which completely burn the coking gases evolving on coal carbonization and which utilize the heat of combustion from coking gases to heat the coal during the coke making process. With the “Heat-Recovery” type, the heat from burnt coking gas utilized to heat the coal cake is additionally exploited by a steam generator to generate energy, for example by means of a turbine installed further downstream. Coke ovens are typically utilized in configurations of several coke oven chambers arranged one behind the other, with consecutively arranged configurations of coke oven chambers of the “Non-Recovery” or “Heat-Recovery” type being called coke oven banks, and consecutively arranged configurations of coke oven chambers of the conventional type being called coke oven batteries.
A controlled combustion of coking gas in two steps calls for a precisely dosed supply of air both into the primary combustion space and into the secondary combustion space of a coking chamber. Devices known from prior art technology, however, frequently are of a very simple design and configuration so that a precisely dosed proportioning is impossible or they are so arranged that a distribution of combustion air can only be accomplished at a few or hardly accessible positions of a coke oven chamber. For the supply of secondary combustion air, a dosed proportioning of air supply in general is simpler, because the supply is not accomplished directly into the secondary combustion space, but via so-called secondary air soles arranged beneath the secondary combustion heating space and connected via the vertical channels to the actual secondary heating space.
WO 2006/128612 A1 describes a device for supplying primary combustion air into a coking chamber of a “Non-Recovery” or “Heat-Recovery” type coke oven. By way of this device, spatially uneven ventilation of the primary heating space of the coking chamber and uneven heat distribution in the coking chamber are prevented. By way of this device, primary air is admitted at a plurality or multitude of positions in the top ceiling of the coke oven chamber so that the admittance of primary air is exactly rated and variably controlled throughout the duration of the coking time. The device prevents immediate reaction of aspirated combustion air as it enters into the oven and limits combustion only to the entry area of primary air. The control of air admittance is accomplished by a control element not described here more closely.
U.S. Pat. No. 6,187,148 B1 describes a valve as a device for regulating a pressure setoff between primary heating space and secondary heating space or secondary air soles of a “Non-Recovery” or “Heat-Recovery” type coke oven which is utilized to establish a pressure setoff between primary heating space and secondary heating space of a coke oven chamber. Since a negative pressure prevails in the coke oven chamber especially at the beginning of the coking process as the cold coal cake is pressed in, the admittance of primary air which in the afore-mentioned teaching is accomplished through apertures in the coke oven chamber door and in flaps arranged there above, is only poorly controllable. For this reason, the invention provides for valves in the “downcomer” channels which cater for a pressure setoff between the primary heating space and secondary heating space of a coke oven chamber. If required, the valves can also be utilized for admitting secondary combustion air into the secondary heating space. A control of the admittance of primary combustion air is not described. The valves are easy to handle, because they are accommodated in the coke oven chamber sides averted from the door and because they are equipped with a revolving tube serving as shutoff device. A revolving tube, however, tends to get stuck at prevailing high temperatures and therefore it is susceptible to repairs. Likewise, the space demand for such a device is quite substantial.
CN 1358822 A describes a coke oven which essentially consists of a furnace body, a coke-oven chamber main wall, a furnace bottom, a furnace door with an adapted furnace door opening, a coal-charging machine, a coke-pushing machine, a coke-receiving device with quenching device and a component repair machine with iron tools. By adapting the arched furnace top, a primary-air regulating device, a secondary-air regulating equipment, upward and downward furnace wall holding devices, double-coupled air holes and fourfold-coupled furnace bottom arches, sandwich-type air feed devices and a bottom-based door support structure it is possible to raise the coke quality with varying feed coal types while further reducing the coke cost and ensuring good heat recovery. The teaching describes a flap for primary-air apertures on the ceiling of coke-oven chambers, the movement and operation mechanism of which, also in dependence of the carbonization process, is not disclosed in more detail.
DE 102005015301 A1 describes a method for the production of coke in a coke-oven chamber of a “Heat-Recovery” or “Non-Recovery” type coke oven, according to which the coke-oven chamber is filled with a layer of coal, the coal is heated, and volatile coal components degas from the coal, these volatile coal components partially oxidize directly above the coal layer, a combustion system is arranged beneath the coke-oven chamber and used for the combustion of not yet combusted volatile coal components as well as the gases generated in the partial oxidation, the coke-oven chamber contains side walls being provided with channels, these channels connecting the upper, coke-free part of the coke-oven chamber on the gas side with the combustion system arranged below the coke-oven chamber, the volatile coal components partially oxidize above the coal layer are conveyed via the channels to the combustion systems arranged beneath the coke-oven chamber, both the coke-oven chamber and the combustion system are equipped with devices for the restricted admittance of air, the combustion of the volatile coal components by means of air being at first accomplished only incompletely as partial oxidation in both the coke-oven chamber above the coal layer and also in the combustion system located below, and the complete combustion is accomplished later in a separate final combustion system which is arranged outside both the coke-oven chamber and the combustion system located beneath the coke-oven chamber. The teaching discloses adjustable air inlets on the ceiling of the coke-oven chamber, the detailed design of which, however, is not described.
WO 2007057076 A1 describes an aeration device for “Non-Recovery” type coke ovens, with the aeration device consisting of at least one opening which passes through the wall or through internals such as, for example, the oven door and connects the oven interior with the outer atmosphere surrounding the oven and can be wholly or partly closed by means of a closure element. In this case two or more of these closure elements are coupled by means of at least one mechanical connecting element such that the connecting element is fastened directly or via a lever to the closure elements, and each connecting element is connected to at least one central actuating element in such a manner that the closure elements can be moved, with the respective openings allowing closure, complete opening or setting to any intermediate position. The openings for the feed of primary air into the coke-oven chambers are provided in the coke-oven chamber doors so that the primary air enters the coke-oven chamber only in the surrounding of the coke-oven chamber doors. The adjustment is typically accomplished by a cover plate or screw spindles, by which precise adjustment is problematic under certain operating conditions and rain showers pose a problem.
Therefore, it would be of substantial benefit to avail of a simple device by means of which primary combustion air is conducted through the top ceiling of a coke oven chamber, with it being possible for this device to be comprised of a simple tube, shut-off by another device or controlled in a dosed manner in terms of its gas flow rate. Conducting it through the top ceiling is much simpler and requires less space. Moreover, mounting the control device outside the coke oven chamber and outside the actual air supply device would be much simpler and easier to service.